One of the particular cases of census, but at the same time one of the most common, is the so-called population census, in which the objective is to determine the number of people that make up a group, usually a country or a nation. In this case, the statistical population would include the components.

In general, a population census can carry out some extra activities that do not specifically correspond to the statistical census operation. The aim is to calculate the number of inhabitants of a country with a delimited territory, corresponding to a given moment or period, but it is also used to obtain a series of demographic, economic and social data related to those inhabitants, considered from a quantitative point of view. It is the primary source of basic population statistics that are necessary for government purposes and aspects of economic and social planning.

There are two types of population censuses:[5]​.

• - De facto census or de facto: all the people who will be in the dwelling or enumeration control unit are listed, on the date and time that has been designated for the census (whether or not they reside in said housing unit).

• - Census de jure o de jure: the person is enumerated in the place where he or she usually resides (whether he or she is living at home or not). This second alternative offers greater operational difficulties than the first.

Individuals within households are typically counted and information on household and housing structure is typically collected. For this reason, international documents refer to population and housing censuses. Normally, the response to the census is made by a household, indicating details of the people who reside there. An important aspect of census enumerations is determining which individuals can be counted and which cannot. In general terms, as mentioned above, three definitions can be used: de facto residence; residence of law; and permanent residence. This is important when considering people who have multiple or temporary addresses. Each person must be uniquely identified as residing in a location; but where they are on Census day, their de facto residence, may not be the best place to count them. Where an individual uses the services it may be most useful, and that is in their habitual residence. An individual may be registered at a "permanent" address, which could be a family home for students or long-term immigrants.[6]​.

A precise definition of residence is needed to decide whether or not visitors to a country should be included in the population count. This is becoming more important as students travel abroad to study over a period of several years. Other groups that cause registration problems are newborns, refugees, people on vacation, those moving home on census day, and people with no fixed address.

People with second homes because they work in another part of the country or have a vacation home are difficult to pin down at a specific address; This sometimes results in double counting or homes being misidentified as unoccupied. Another problem is when people use a different address at different times, e.g. students who live at their place of education during term time but return to a family home during the holidays, or children whose parents have separated and who effectively have two family homes. Census enumeration has always been based on finding people where they live, as there is no systematic alternative: any list used to find people is likely to be derived from census activities in the first place. Recent UN guidelines offer recommendations on how to list such complex homes.[7]​.

In the agricultural census, data are collected at the agricultural holding unit. A farm is an economic unit of agricultural production under single management that comprises all livestock raised and all land used in whole or in part for the purposes of agricultural production, regardless of its title, legal form or size. Sole management may be exercised by an individual or household, jointly by two or more individuals or households, by a clan or tribe, or by a legal entity such as a corporation, cooperative, or government agency. The farm's land may consist of one or more plots, located in one or more separate areas or in one or more territorial or administrative divisions, provided that the plots share the same means of production, such as labor, agricultural facilities, machinery or draft animals.[1]​.

Historical censuses used crude enumeration assuming absolute precision. Modern approaches take into account problems of overcounting and undercounting, and the consistency of census enumerations with other official data sources[8]​ An important aspect of the census process is evaluating data quality.[9]​.

Many countries use a post-enumeration survey to adjust raw census counts.[10] This works in a similar way to capture-recapture estimation of animal populations. Among census experts, this method is called dual system enumeration (DSE). Interviewers visit a sample of households and record household details on census day. This data is then compared to census records, and the number of people missed can be estimated by considering the number of people who are included in one count but not the other. This allows adjustments to the nonresponse count, which varies between different demographic groups. An explanation using a fishing analogy can be found in "Trout, Catfish and Roach...",[11]​ which won an award from the Royal Statistical Society of the United Kingdom for excellence in official statistics in 2011.

The triple enumeration system has been proposed as an improvement, since it would allow the statistical dependence of pairs of sources to be evaluated. However, as the matching process is the most difficult aspect of census estimation, it has never been implemented for a national enumeration. It would also be difficult to identify three different sources that were different enough to make the three-way system worthwhile. The DSE approach has another weakness: it assumes that no person is counted twice (overcounting). Under de facto residency definitions this would not be a problem, but under de jure definitions individuals run the risk of being recorded on more than one form, which would result in double counting. A particular problem here is students who often have a class schedule and a family address.

Several countries have used a system known as short form/long form.[12] This is a sampling strategy that randomly chooses a proportion of people to send a more detailed questionnaire (the long form). Everyone gets the short questions. This means more data is collected, but without imposing a burden on the entire population. This also reduces the burden on the statistical office. In fact, in the United Kingdom until 2001 all residents were required to complete the entire form, but only a sample of 10% was coded and analyzed in detail.[13]​ New technology means that all data is now scanned and processed. During the 2011 Canadian census there was controversy over the cessation of the mandatory long-form census; The head of Statistics Canada, Munir Sheikh, resigned following the federal government's decision to do so.[14]​.

The use of other alternative enumeration strategies is increasing,[15]​ but they are not as simple as many people assume and are only used in developed countries.[16]​ The Netherlands has been the most advanced country in adopting a census using administrative data. This allows a simulated census to be carried out by linking several different administrative databases at an agreed time. Data can be collated and a general enumeration established that allows for discrepancies between different data sources. A validation survey is still conducted in a manner similar to the post-enumeration survey employed in a traditional census.

Other countries that have a population registry use it as the basis for all census statistics that users need. This is most common among the Nordic countries, but requires many different registers to be combined, including population, housing, employment and education. These records are then combined and brought to the standard of a statistical record by comparing data from different sources and ensuring that the quality is sufficient for official statistics to be produced.[17]​.

A recent innovation is the French initiative of a rolling census program in which different regions are enumerated each year, so that the entire country is completely enumerated every 5 to 10 years.[18]​ In Europe, in connection with the 2010 round of censuses, many countries adopted alternative census methodologies, often based on combining data from registers, surveys and other sources.[19]​.

The word census is derived from the republican era of Roman History that begins with the end of the Monarchy in the year 509 BC. C. From then on, the functions of the kings were replaced by what is known as the Roman institutions or magistracies: consul, praetor, censor and other later ones. Censorship was a magistracy created in the year 443 BC. C. and had among its powers those of carrying out the census (hence its name), supervising public morality (censorship), reviewing the list of citizens and that of the Senate, and certain aspects of public finances, such as deciding which public works were going to be paid for by the Republic in the following five years (lustrum or five years, which was the length of service in said magistracy).

Censuses are a very valuable source of information for genealogists, as they provide information about ancestors and their families, such as name, age, place of birth, marital status, occupation, nationality, religion, educational level, and household composition. In addition, censuses can help place ancestors in a historical and social context, and trace them over time and space.[20]​.

• - Demographics.

• - Electoral census.

• - Municipal register of inhabitants.

• - Survey.

• - Population censuses by country worldwide.

Literature

• - Wiktionary has definitions and other information about census.

• - National Institute of Statistics and Censuses of the Argentine Republic.

• - Brazilian Institute of Geography and Statistics - IBGE.

• - National Institute of Statistics of Chile.

• - National Administrative Department of Statistics or DANE - Colombia.

• - Census Bureau, United States Census Bureau.

• - National Institute of Statistics and Geography of Mexico.

• - General Directorate of Statistics, Surveys and Censuses of Paraguay.

• - National Institute of Computer Statistics of Peru Archived April 12, 1997 at the Wayback Machine.

• - National Statistics Office of the Dominican Republic.

• - National Institute of Statistics of Venezuela.

• - Buenos Aires 1855 Census, history and particular characteristics.

The census is carried out through the application of statistical monitoring or survey to the entire objective population; In this, all the numbers of said operation are reduced;[3]​ then, this information serves as a framework for carrying out future sampling when it is not possible to carry out a census, whether they are statistically representative (probabilistic) or not.[4]​

Thus, if the target population is the inhabitants of a city or country, for the disclosure to be census-based, all the people who live in the city or country must be interviewed. However, whether or not it is appropriate to carry out a sampling or census procedure will depend specifically on the existing populations and error sizes. While in the first case the presence of a sampling error is observed.

One of the particular cases of census, but at the same time one of the most common, is the so-called population census, in which the objective is to determine the number of people that make up a group, usually a country or a nation. In this case, the statistical population would include the components.

In general, a population census can carry out some extra activities that do not specifically correspond to the statistical census operation. The aim is to calculate the number of inhabitants of a country with a delimited territory, corresponding to a given moment or period, but it is also used to obtain a series of demographic, economic and social data related to those inhabitants, considered from a quantitative point of view. It is the primary source of basic population statistics that are necessary for government purposes and aspects of economic and social planning.

There are two types of population censuses:[5]​.

• - De facto census or de facto: all the people who will be in the dwelling or enumeration control unit are listed, on the date and time that has been designated for the census (whether or not they reside in said housing unit).

• - Census de jure o de jure: the person is enumerated in the place where he or she usually resides (whether he or she is living at home or not). This second alternative offers greater operational difficulties than the first.

Individuals within households are typically counted and information on household and housing structure is typically collected. For this reason, international documents refer to population and housing censuses. Normally, the response to the census is made by a household, indicating details of the people who reside there. An important aspect of census enumerations is determining which individuals can be counted and which cannot. In general terms, as mentioned above, three definitions can be used: de facto residence; residence of law; and permanent residence. This is important when considering people who have multiple or temporary addresses. Each person must be uniquely identified as residing in a location; but where they are on Census day, their de facto residence, may not be the best place to count them. Where an individual uses the services it may be most useful, and that is in their habitual residence. An individual may be registered at a "permanent" address, which could be a family home for students or long-term immigrants.[6]​.

A precise definition of residence is needed to decide whether or not visitors to a country should be included in the population count. This is becoming more important as students travel abroad to study over a period of several years. Other groups that cause registration problems are newborns, refugees, people on vacation, those moving home on census day, and people with no fixed address.

People with second homes because they work in another part of the country or have a vacation home are difficult to pin down at a specific address; This sometimes results in double counting or homes being misidentified as unoccupied. Another problem is when people use a different address at different times, e.g. students who live at their place of education during term time but return to a family home during the holidays, or children whose parents have separated and who effectively have two family homes. Census enumeration has always been based on finding people where they live, as there is no systematic alternative: any list used to find people is likely to be derived from census activities in the first place. Recent UN guidelines offer recommendations on how to list such complex homes.[7]​.

In the agricultural census, data are collected at the agricultural holding unit. A farm is an economic unit of agricultural production under single management that comprises all livestock raised and all land used in whole or in part for the purposes of agricultural production, regardless of its title, legal form or size. Sole management may be exercised by an individual or household, jointly by two or more individuals or households, by a clan or tribe, or by a legal entity such as a corporation, cooperative, or government agency. The farm's land may consist of one or more plots, located in one or more separate areas or in one or more territorial or administrative divisions, provided that the plots share the same means of production, such as labor, agricultural facilities, machinery or draft animals.[1]​.

Historical censuses used crude enumeration assuming absolute precision. Modern approaches take into account problems of overcounting and undercounting, and the consistency of census enumerations with other official data sources[8]​ An important aspect of the census process is evaluating data quality.[9]​.

Many countries use a post-enumeration survey to adjust raw census counts.[10] This works in a similar way to capture-recapture estimation of animal populations. Among census experts, this method is called dual system enumeration (DSE). Interviewers visit a sample of households and record household details on census day. This data is then compared to census records, and the number of people missed can be estimated by considering the number of people who are included in one count but not the other. This allows adjustments to the nonresponse count, which varies between different demographic groups. An explanation using a fishing analogy can be found in "Trout, Catfish and Roach...",[11]​ which won an award from the Royal Statistical Society of the United Kingdom for excellence in official statistics in 2011.

The triple enumeration system has been proposed as an improvement, since it would allow the statistical dependence of pairs of sources to be evaluated. However, as the matching process is the most difficult aspect of census estimation, it has never been implemented for a national enumeration. It would also be difficult to identify three different sources that were different enough to make the three-way system worthwhile. The DSE approach has another weakness: it assumes that no person is counted twice (overcounting). Under de facto residency definitions this would not be a problem, but under de jure definitions individuals run the risk of being recorded on more than one form, which would result in double counting. A particular problem here is students who often have a class schedule and a family address.

Several countries have used a system known as short form/long form.[12] This is a sampling strategy that randomly chooses a proportion of people to send a more detailed questionnaire (the long form). Everyone gets the short questions. This means more data is collected, but without imposing a burden on the entire population. This also reduces the burden on the statistical office. In fact, in the United Kingdom until 2001 all residents were required to complete the entire form, but only a sample of 10% was coded and analyzed in detail.[13]​ New technology means that all data is now scanned and processed. During the 2011 Canadian census there was controversy over the cessation of the mandatory long-form census; The head of Statistics Canada, Munir Sheikh, resigned following the federal government's decision to do so.[14]​.

The use of other alternative enumeration strategies is increasing,[15]​ but they are not as simple as many people assume and are only used in developed countries.[16]​ The Netherlands has been the most advanced country in adopting a census using administrative data. This allows a simulated census to be carried out by linking several different administrative databases at an agreed time. Data can be collated and a general enumeration established that allows for discrepancies between different data sources. A validation survey is still conducted in a manner similar to the post-enumeration survey employed in a traditional census.

Other countries that have a population registry use it as the basis for all census statistics that users need. This is most common among the Nordic countries, but requires many different registers to be combined, including population, housing, employment and education. These records are then combined and brought to the standard of a statistical record by comparing data from different sources and ensuring that the quality is sufficient for official statistics to be produced.[17]​.

A recent innovation is the French initiative of a rolling census program in which different regions are enumerated each year, so that the entire country is completely enumerated every 5 to 10 years.[18]​ In Europe, in connection with the 2010 round of censuses, many countries adopted alternative census methodologies, often based on combining data from registers, surveys and other sources.[19]​.

The word census is derived from the republican era of Roman History that begins with the end of the Monarchy in the year 509 BC. C. From then on, the functions of the kings were replaced by what is known as the Roman institutions or magistracies: consul, praetor, censor and other later ones. Censorship was a magistracy created in the year 443 BC. C. and had among its powers those of carrying out the census (hence its name), supervising public morality (censorship), reviewing the list of citizens and that of the Senate, and certain aspects of public finances, such as deciding which public works were going to be paid for by the Republic in the following five years (lustrum or five years, which was the length of service in said magistracy).

Censuses are a very valuable source of information for genealogists, as they provide information about ancestors and their families, such as name, age, place of birth, marital status, occupation, nationality, religion, educational level, and household composition. In addition, censuses can help place ancestors in a historical and social context, and trace them over time and space.[20]​.

• - Demographics.

• - Electoral census.

• - Municipal register of inhabitants.

• - Survey.

• - Population censuses by country worldwide.

Literature

• - Wiktionary has definitions and other information about census.

• - National Institute of Statistics and Censuses of the Argentine Republic.

• - Brazilian Institute of Geography and Statistics - IBGE.

• - National Institute of Statistics of Chile.

• - National Administrative Department of Statistics or DANE - Colombia.

• - Census Bureau, United States Census Bureau.

• - National Institute of Statistics and Geography of Mexico.

• - General Directorate of Statistics, Surveys and Censuses of Paraguay.

• - National Institute of Computer Statistics of Peru Archived April 12, 1997 at the Wayback Machine.

• - National Statistics Office of the Dominican Republic.

• - National Institute of Statistics of Venezuela.

• - Buenos Aires 1855 Census, history and particular characteristics.